Piston



Aug. 4, 1936.

G. c. NIENOW 2,049,922

PISTON Filed Sept. 12, 1935 /N ws/vroe George C /V/'enow BY H/s Arm/avers Patented Aug. 4, 1936 To s'r'rs i p g M 2,049sz2 V-ATETI QFiig 1 My invention relates to pistons and more particularly to pistons of the type used in internal combustion engines, and has for its object to provide a piston that will automatically adapt itself to wear; will always maintain close engagement with the walls of the cylinder, thereby preventing back lash or side slap; which may be readily repaired in case of excessive wear or breakage; and in which the head and skirt portions of the piston may, when found desirable, be made of diiferent metals to better adapt the same to the conditions to which the respective parts are subject to wear.

In accordance with the objects of this invention, the piston is made with independently renewable and replaceable sections and in which, when assembled, the skirt-forming portions or sections are interlockedto the head for common movement therewith. The skirt sections are subjected to a slight pressure from a yielding element, such as a spring or springs, which maintain engagement between the skirt sections and the cylinder walls irrespective of expansion and contraction of the cylinder and piston-forming elements.

The manner is which these features are carried into practice in the preferred form of the commercial device is illustrated in the accompanying drawing, wherein like characters indicate like parts throughout the several views.

Referring to the drawing:

Fig. 1 is a perspective showing the complete piston with the parts thereof assembled;

Fig. 2 is an axial sectional view taken on the line 22 of Fig. 1;

Fig. 3 is a fragmentary sectional view taken on the line 3-3 of Fig. 2;

Fig. 4 is a perspective showing one of the skirt forming sections of the piston, looking .at the same from the inner side thereof; and

Fig. 5 is a perspective showing the wrist pin of the piston removed from the other parts thereof.

The head-forming portion 6 of the piston is a cast structure externally formed with grooves to receive piston rings 1. The skirt of the piston is formed in two sections 8 that are detachable from the head. The skirt sections 8 are formed with inwardly projecting axially alignable hollow hubs 9 that afiord wrist pin seats, the outer extremities of which are closed by the walls of the skirt sections. The piston head, at diametrically opposite points, is provided with diametrically opposite depending lugs I with axially aligned holes that afiford hub seats into which the hubs 9 01 the respective pistons are adapted to be telescoped, as best shown in Fig. 2. When the skirt sections are in position with their'wrist pin seating hubs Q telescoped into their seats in the respective lugs iii, the said skirt sections will be interlocked to the head against axial movements in respect thereto, but free for lateral movements to and from working positions. Of course, when the head and skirt sections are assembled as just stated and placed within a cylinder, the skirt 10 and head portions of the piston will be held together for movements as an integral piston structure.

By reference particularly to Fig. 2, it will be noted that the reduced upper edge portions of the skirt sections 8 are lapped with the lower portion. of the head 6 so that the skirt sections are held in true axial alignment with the head. To stiffen the skirt sections, they are shown as provided with integral ribs I I. It is important to further note, see particularly Fig. 1, that the skirt sections, at their abutting edges, are joined by lapped joints l2 that extend obliquely in respect to lines parallel to the axis of the piston, so as to prevent the wearing of grooves in the cylinder wall and further to form tight joints between the adjoining edges of the skirt sections.

The wrist pin l3, at its ends, is insertable into the seats afiorded by the hubs 9 of the two skirt sections. To provide the yielding pressure for keeping contact between the skirt sections and the cylinder wall, yielding devices such as coiled springs l4 are interposed between the ends of the wrist pin and the closed extremities of the hubs 9. These springs produce yielding force against the skirt sections, which maintains engagement between the skirt sections and the cylinder wall. As shown, the springs M are set somewhat into seats formed in the ends of the wrist pin. When the wrist pin is applied as indicated, as shown, in Fig. 2, the intermediate portion thereof will be exposed between the hubs 9 so that the connecting rod, not shown, may be applied to said wrist pin.

In practice, it will be possible either to mount the connecting rod loosely on the wrist pin or to releasably connect the connecting rod to said wrist pin. In the former case, the frictional movement due to oscillations could be taken either between the wrist pin and the connecting rod, or between the wrist pin and the lugs 9, or at both places. In the second assumed case, the frictional movement due to oscillation would take place entirely between the wrist pin and lugs 9. In either case, there would be no possibility of the ends of the wrist pin ever coming in contact -With the walls of the cylinder.

As a summary of the advantages of this improved piston, it may be stated that it eliminates danger of loose piston pins which, when loose, may score the cylinder walls; it reduces the piston side slap with resulting noise and wear; it saves oil by having perfect fit to the cylinder walls. It increases the power by keeping piston head and rings in alignment with the cylinder; and decreases the necessity of having cylinders rebored.

It will, of course, be understood that the piston, the preferred form of which is illustrated in the drawing, is capable of various modifications within the scope of the invention herein disclosed and claimed.

What I claim is:

1. In a piston, a head member having hub-receiving portions, skirt sections having hubs directly seated in the hub-receiving portions of said head, and a wrist pin seated in the hubs of said skirt sections and having an exposed intermediate portion for the application of a connecting rod thereto.

2. In a piston, a head member having lugs, approximately semi-cylindrical skirt sections having hubs seated in the lugs of said head, and a wrist pin seated in the hubs of said skirt sections and having an exposed intermediate portion for the application of a connecting rod thereto.

3. The structure defined in claim 1 in which said skirt sections have overlapping joints with said head.

4. The structure defined in claim 1 in which said wrist pin is tubular, and in further combination with a coiled spring contained in said wrist pin and yieldingly pressing said skirt sections outward.

5. The structure defined in claim 2 in which said wrist pin is tubular, and in further combination with a coiled spring contained in said wrist pin and yieldingly pressing said skirt sections outward.

GEORGE C. NIENOW. 

